Silencer



Aug. 31 1926. 1,598,578

- H. P. MAXIM SILENCER Filed NOV. 21, 1921 2 Sheets-Sheet 1 INVENTOR 1 7 W" a BYZL W ATTORNEYS Aug. 31 1926. 1,598,578

H. P. MAXIM SILENCER Filed NOV. 21, 1921 2 Sheets-Sheet 2 lj/7 M.

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Patented Aug. 31, 1926.

; UNITED "STATES. PATENT OFFICE. I

mm PERCY MAXIM, OF HARTFORD, CONNECTICUT, ASSIGNOR TO MAXIM SILENCER COMPANY, OF HARTFORD, CONNECTICUT, A CORPORATION OF CONNECTICUT.

- SILENCER.

Application filed November2l, 1921. Serial No. 516,814.

The gases are admitted to the central cham-- 1 her through a port in one of the header plates and are caused, by suitably arranged perforationsin the central and intermediate tubes, to travel in reversed directions through the three mufiler chambers. The

2 hot gases cause the sheet metal tubes and connecting bolts to expand toa different extent and as a result the tubes eventually become loosened or distorted so that they rattle disagreeably.

2 One of the objects ofthe present invenculty and to this end the invention contemplates the provision ofa silencer having a plurality of interconnected. concentric chambers affording afcontinuou's tortuous passage for the gas and sound waves, which chambers are so arated by partition walls thatare supporte at one end only and are thus enabled to expand and contract freely without becoming loosened. In the preferred embodiment of this feature of the invention, a plurality of tubes are concentrically arranged between headermembers, and alter nate tubes are secured at one end to opposite header members leaving the other ends of the tubes unsupported so that the tubes mayexpand and contract freely under different temperature conditions without be coming loosened or distorted. l5 .Other objects of the invention are to provide a silencer of fabricated construction which is particularly designed for economical quantity production, to provide a light weight silencer having a simplified and i0 thoroughly practical structure, to provide a silencer of the general type above indicated comprising a minimum number of component parts and to provide a silencer the parts of which may be easily and quickly assembled. I I

tion is to avoid the abovementioned' ditfi For the accomplishment of these objects and such others as may hereinafter appear, the invention consists in the features of construction and in the combinations and arrangements of parts hereinafter described and claimed, the particular advantages of which willbe obvious to those skilled in the art.

The various features of the invention will be readily understood from the following description of the several forms thereof illustrated in the accompanying drawings, in which Fig. 1 is a view in longitudinal section of a silencer constructed in accordance with what may be considered the preferred embodiment of the present invention;

- Fig. 2 is a sectional view taken alongthe line 2-2 'of Fig. 1;

Fig. 3 is a view similar to Fig. 1, showing a silencer having an alternative form of construction Fig. 4 is a view, partially in longitudinal section and partially in elevation, illustrating another aternative form of silencer construction;

Fig. 5 is a sectional detail view illustrating a feature of the invention relating to the construction of the tubular sheet metal members forming the concentric mufiler chambers.

Referring to Figs. 1 and 2 of the "drawings, the improved silencer therein illustrated is of fabricated construction and is composed entirely of sheet metal parts that are rigidly secured in assembled relation by means of tie-bolts. These sheet metal parts comprise an outer cup-like shell 15, a pair of annular channel members 16 and 17 which are adapted for assembly within the shell 15, and a fiat disk or header plate v18 for closing one end of the silencer. The shell is a one piece integral construction drawn into its finished shape from a circular sheet metal blank. As shown, the shell, has a cylindrical sidewall and a fiat end wall, the latter having an annular flange drawn lengthwise from a central opening therein to form a tubular conductor 19 coaxial with the cylindrical sidewall of said shell and affording a port or passage 20 for the admis sion to the silencer of the gases and sound waves.

The channel members 16 and 17 are also, each of one piece construction, drawn from circular sheet metal blanks and these menibers have cylindrical side walls and flat annular end walls, the side walls of one member being of greater diameter than the corresponding side walls of the other member. By virtue of this construction, the two channel members 16 and17 are adapted for assembly with the mouths of the channels oppositely directed and with one side wall of each member interposed between and spaced from the side walls of the other member. The end wall of the smaller channel member 17 is adapted for engagement with the end wall of the shell 15, while the end wall of the larger channel member 16 is adapted to be overlapped by the marginal portion of a disk or header plate 18.

In the present instance four tie-bolts 22 are employed to maintain the parts of the silencer in the assembled relation above specified, although obviously, a greater or less number of tie-bolts may be used if desired. The tie-bolts 22 are disposed longitudinally of the silencer and extend through the annular space which is common to the two assembled channel members, i. e. the space between the outer side wall of the smaller member 17 and the inner side wall of the larger member 16. At their ends, the tie-bolts 22 project through suitable holes in the end walls of the channel members, in the end wall of the shell 15, and in the margin of the header plate 18. As shown, the portion of each tiebolt between the opposed end walls of the two channel members is square in cross-section and the opposite ends of the bolt-s are screw-threaded to receive clamping nuts 28. By thus using square bolts, suitable shoulders are provided for cooperating with the nuts 23 without the necessity of reducing the diameter of the threaded ends of the bolts. By tightening the nuts 23 the end wall of the shell 15 will be rigidly secured to the end wall of the channel member 17 while the header plate 18 will be rigidly secured to the end wall of the channel member 16. The length of the square portions of the tie bolts is such that the peripheral edges of the channel members will be spaced from the opposed end faces of the other channel memhere or of the shell 15, as the case may be.

When assembled, the several component parts of the device will then be arranged in the positions clearly shown in Fig. 1. \Vhen the parts are thus assembled a central muftler chamber 25 is provided between the inner side walls of the smaller channel member 17, and this chamber communicates at one 7 shell 15 and the adjacent outer side wall of the larger channel member.

In'the above described silencer, inasmuch as the cylindrical walls separating the several concentric annular chambers are supported at one end only, these walls are enabled to expand and contract freely under diflerent temperature conditions and consequently they have no tendency to become distorted and loosened as they are repeatedly subjected to the heating action of the gases. The various parts are so firmly bound together by the tie-bolts that there is no tendency for them to work loose as a result of the vibration and shocks to which they are subjected while the car is running. By designing the parts so that they may be drawn into shape from sheet metal blanks these parts can be produced very rapidly and at a very low cost when manufactured in large quantities. The cost of manufacture of the silencers is further decreased by reason of the small number of parts to be assembled and the facility with which the assembly and securing together of these parts may be effected. Furthermore, by the use throughout the silencer of thin sheet metal walls and partitions, a silencer of very light weight has been provided.

The particular type of construction above described is especially adapted for silencers to be used on automobiles, farm. engines, and small stationary engines where it is essential that the silencers shall be sold at a low price. In manufacturing silencers of larger diameter, however, for use in connection with the more powerful engines, such for-example as air-ship engines, it may be impracticable to produce silencer parts of the requisite size by means of deep drawing operations. To enable certain features of the hereinbefore described construction and arrangement of parts to be utilized in connection with the construction of silencers of large sizes, a modification of the'present invention contemplates the production of the outer shell and the two channel members of the silencer each from several sheet metal blanks secured together by the process of oxywelding.

Theabove mentioned construction is illustrated in Fig. 3. As therein shown, the cuplike shell within which the channel members are assembled, is made in three parts,

the difficulties of drawing, and while it is" the flange 34, said tubes being arranged'to, extend in opposite directions from the disk 32 so as toflform a member of substantially the same shape as the outer shell 15 in the form of silencer illustrated in Fig. 1.

Each of the channel members of this modification of the invention are constructed of inner a-ndouter tubes 35 and 36 and a sheet preferred form of the invention and are similarly secured in place b tie-bolts of the same construction as those a ready described.

This alternative construction may be employed wherever it is desired to eliminate more e'xpensive in quantity production to produce the silencer parts by oxywelding smaller parts together than by forming the whole from asingle blank by drawing.

operations, the parts may be economically produced in small quantities by the employment of the. above described oxywelding process. It will be seen that the silencer illustrated in Fig. 3 is constructed entirely of sheet metal and the partition walls between the concentric mufller chambers are supported at one end only as in-the preferred form oftheinvention .so that they are free to expand and contract ,without danger of becoming loosened. Furthermore,

the type of construction shown in Fig. 3 possesses the same advantageous features of lightness and ease of assembly-already referred to in connection with the previously described type. 7 a

.Fig. 4 illustrates amufller of a somewhat further modified construction which is made entirely of sheet metal without the deep cup drawing and repeated annealing operations required for the construction in Fig. 1 and without the welding required for the construction in Fig. '3. In this form of silencer theouter shell thereof is sha edsubstantially ias in the forms already escribed but is composed of two parts 43 and 44 which are adapted to be maintained in'as sembled relation to each other by meansof tie-bolts 45 of the same sort as those used in the other forms of silencers. As shown, the part 43 consists of a cylindrical tube having one end thereof turned inwardly at right angles to the side of the tube to form a flange 46. while a similar flange 47 is turned outwardly from one end of the tube '44 and is adapted to overlap the flange 46 as shown. w

In this form of silencer four separate cylindrical tubes 48, 49, 50 and 51 are substituted for the two annular channel mem-. bers of the formpreviously described, the tubes 48 and 50 being provided .at one end with flanges 52 which are overlapped and apertured to receive the tie-bolts 45 and these flanges and also the flanges 46 and 47 are clamped together between the shoulders and nuts at one. end of the tie-bolts so that the parts associated with said flanges are rigidly secured in place. The tubes 49 and 51 are similarly flanged as shown at 53, the flanges 53 overlapping and being apertured to receive the opposite ends of the tie-bolts. The flanges 53 together with the marginal 9 portion of an end plate 54, through which the tie-bolts also extend, are clamped between the adjacent shoulder and nuts of the tie-bolts. Itwill be seen that the general relation of the passages in this form' of silencer are the same as in the preceding forms and the gases and sound waves will travel through the same course and be similarly acted upon therein.

To assist in breaking up the sound waves 0 as the latter pass through any of the above described'silencers the opposite side walls of each annular muflier-passage may be provided with'annular portions 64 which are inclined inwardly with respect to the di-v rection of travel of the Waves through said chambers to provide what may be termed reverse megaphone sections 65. These sections 65 will be engaged by a certain number of the sound waves advancing through the muffler chambers and will operat'e'to prevent further advance thereof. The angle of inclination of the wall portions 64 is not sufficient however to appreciably retard the flow of the gases through the mufller chamw of the invention is defined by the appended v i,

claims; rather than by the foregoing description. p

What I claim is: 1. Ina silencer of the type having a series, of interconnected concentric chambers affording a continuous tortuous passage for the gases and sound waves, a plurality of spaced elongated cylindrical partition walls separating said chambers, oppositely facing header members for completely closing the opposite ends of said chambers, said partition walls being supported alternately from opposite header members, and tie bolts connected to said header members and means on said bolts between said header members for spacing the same apart a distance greater than the length of said partition walls, whereby the ends of said partition walls and the adjacent header members will be separated by passages afiording the means of communication between adjacent concentric chambers.

2. In a silencer of the type having a series of interconnected concentric chambers affording a continuous tortuous passage for the gases and sound waves, a plurality of spaced elongated cylindrical partition walls separating said chambers, header members separable from said partition walls for closing the opposite ends of said chambers, and tie-bolts serving both for supporting the header members in spaced relation and for rigidly securing the partition walls to the header members' 3. In a silencer of the type having a series of interconnected concentric chambers affording a continuous tortuous passage for the gases and sound waves, a plurality of separable annular channel members each having an annular base and side walls perpendicular to said base, said members being adapted for assembly in reversed positions with their annular bases spaced apart and in coaxial relation,with one side wall of each channel member interposed between and spaced from the side walls of the other channel member and from the annular base of said member, spaced apart header plates for supporting said channel members, and tie bolts serving both for securing the annular bases of said channel members to the header plates and to rigidly maintain the channel members in the relation to each other above specified.

4. A silencer comprising a plurality of separable annular channel members adapted for assembly in reversed positions with their annular bases spaced apart and in coaxial relation, with one side wall of one member interposed between and spaced from the side walls of an adjacent member, and a plurality of bolts extending axially through the channels and bases of one or more of said other member, thereby providing a series.

of interconnected concentric chambers affording a continuous tortuous passage for the gases and sound waves. r

5( A silencer comprising a cup member having a base centrally apertured for the passage of the sound propagating medium, two separable annular channel members of diilerent diameters adapted for assembly in reversed positions with their annular bases spaced apart and coaxial with said cup member with one side wall of each channel member interposed between and spaced from the side walls of the other channel member and the outer side wall of the larger channel member spaced from the side wall of said cup member, a disk for closing the central passage through the larger channel member at one end of the silencer, and means serving both for securing the annular base of the smaller channel member to the base of said cup member and the marginal portion of said disk to the annular base of the larger channel member and for maintaining the channel members with their side walls in the relation specified and with the peripheral edges of each channel member spaced from the annular base of the other channel member.

6. A silencer comprising a cup member having a base centrally apertured for the passage of the sound propagating medium, a separable annular channel member coaxially disposed within said cup member with its annular base secured to the base of said cup member, a second separable annular channel member having its inner side wall interposed between and spaced from the side walls of the first channel member and its outer side wall interposed between and spaced from the outer side wall of said channel member and the side wall of said cup member, a disk having its marginal portion secured to the annular base of the second channel member, and means for rigidly maintaining the channel members in the relative positions specified and with the peripheral edges of each of said channel members spaced from the annular base of the other member and for securing the first channel member to said cup member and the second member to said disk.

7. A silencer comprising a cup member having a base centrally apertured and an annular flange outwardly turned in an axial direction from said aperture in its base to provide an inlet conductor for conveying to the silencer the gases and sound waves, a separable annular channel member coaxially 'disposed within said cup member with its annular base secured to the base of said cup member, a second separable annular channel member having its inner side wall interposed between and spaced from the side walls of the first channel member and its outer side wall interposed between and spaced. -from the outer side wall of said channel member and the side wall of said cup member, means for closing the centralpassage through the second channel member at the end remote from the base of said cup .member and means for maintaining the channel members in the relative positions specified and with the peripheral edges of each of said channel members spaced from the annular base of the other channel member. I

8. A silencer comprising a plurality of separable annular channel members adapted 'for assembly in reversed positions with their annular bases spaced apa/I't and in coaxial relation with one side wall of one member interposed between and spaced from the side walls of an adjacent member, and a plurality of tie-bolts extending axially through the channels ofone or more of said channel members, said bolts bein e the inner faces of the opposed annular ases of said members and having screwthreaded ends beyond said shoulders projecting through the bases of said members, an, clamping said members against said shoulders to support said members in the relation specified,'the shoulders of said tie-bolts being located so that the peri heral edges of each channel member will the base of the other channel member.

9. A silencer comprising a plurality of separable annular channel members ada ted for assembly in reversed positions with t eir annular bases spaced apart and in coaxial relation with one side wall of one member interposed between and spaced from the side walls of an adjacent member, and a plurality of the bolts extending axially through the channels of" one or more of said channel members, the o posite ends of the bolts being screw-threa ed and adapted to project through holes in the annular bases members in the relation specified.

10. In a silencer ofthetype having a se-" tending through said disk and through said ries of interconnected concentric chambers affording a continuous tortuous pa e for the gases and sound waves, the PIOVlSlOIl in said chambers intermediate the ends thereof of a longitudinal section of restricted transwerse area interposed between sections of maximum area, said restricted area section having. gradually ta ring side walls for breaking up the soun ciably retarding the passage ofthe medlum of travel of said waves.

' agatin shouldered to end nuts on said threaded boltends forspaced from waves without ap re- 11. A silencer comprising a cup member constructed of separate pieces oined together, said member having a base centrally apertured for the passage of the sound propmedium, two separable annular channe members of fabricated construction and difl'erent diameters adapted for assembly in reversed positions with their annular bases spaced apart and coaxial with said cup member with one side wall of each channel member interposed between and spaced from the side walls of the other channel member and the outer side wall of the larger channel niember spaced from the side wall of said cup member, a disk for closing the central passage through the larger channel member at one end of the silencer, and means serving both for securing the annular base .of the smaller channel member to the base of said cup member and the marginal portion of said disk to the base of the larger channel member and for maintaining the channel members with their side walls in the relation specified and with the peripheral edges of each channel member spaced from the base of the other channel member.

12. A silencer comprising a cup member having an annular flange outwardly turned in an axial direction froman aperture in its base to provide an inlet conductor 'for'conveying to the silencer the gases and sound waves, said cup member constructedof two annular parts having overlapping portions constitutmg said base, a separable annular channel member adapted for assembly within and coaxial with said casing, said member comprising outer and inner concentric side walls having respectively inturned and outturned annular flanges at one end there of arranged in overlappin relation to constitute the annular baseo said member, a

second separable annular. channel member, of greater diameter than the first channel member and similarly constructed, said second cha-nnel'member adapted for assembly in the silencer with its inner side wall interposed between and spaced from the side walls of the "first channel member and its outer side wall interposed between and spaced from the outer side wall of said channel member and the side wall of said cup member, a disk having its marginal portion adapted to overlap the annular base of the second channel member, and tie bolts exoverlapped portions of said cup member and of said channel members to rigidly secure said arts together in the relative positions 'speci ed and with the peri heral edges of HIRAMPERCY MAXIM. 

